The present invention relates to automatic processors of film and similar photosensitive media, in general; and, in particular, to a system for updating processor control circuitry software by downloading software from an external source by means of reprogramming an on-board programmable read-only memory without removal thereof.
Photosensitive media processors, such as the Kodak X-OMAT processors, are useful in applications such as the automatic processing of radiographic films for medical imaging purposes. The processors automatically transport sheets or webs of photosensitive film, paper or the like (hereafter "film") from a feed end of a film transport path, through a sequence of chemical processing tanks in which the media is developed, fixed, and washed, and then through a dryer to a discharge or receiving end. The processor typically has a fixed film path length, so final image quality depends on factors including transport speed which determines length of time the film strip is in solution, and the temperature and composition of the processing chemicals (the processor "chemistry").
In a typical automatic processor of the type to which the invention relates, film transport speed is set at a constant rate and the chemistry is defined according to a preset recommended temperature, e.g. 93.degree. F., with a specified tolerance range of +/-X.degree. F. A temperature control system is provided in the processor to keep the chemicals within the specified range.
Conventional processors usually include a film width sensor in the form of a reflective infrared sensor array adjacent a feed entrance opening, and may also include a feed detector in the form of a Hall effect switch or the like for detecting separation of entrance rollers due to the passage of film sheets at the front end of the transportation path. The film width sensor not only provides an indication of the width of a sheet entering the processor, but may also provide an indication of the occurrence of the leading edge and trailing edge of each sheet, since the signals from the film width sensor will change significantly as each leading and trailing edge is encountered. Information as to leading and trailing edge occurrences and width of the film, taken with prior knowledge of the constant transport speed, is used to keep track of cumulative total film surface area processed in order to guide chemistry replenishment control. The use of a separate entrance roller detector signals that a sheet of film has actually entered the nip of the first roller pair, and is not just sitting still on the film guide under the width sensor.
Although conventional processors used for radiographic image processing are traditionally configured to operate at a constant film transport speed, modifications may be made through gear changes and the like to vary the process. Moreover, new processors are being introduced which are usable in more than one mode. The mode is often referred to in shorthand fashion by a nominal film transport "drop time", which may be defined as the time from entry of the leading edge of a sheet of film at the feed end until exit of the trailing edge of the same sheet of film at the discharge end. Conventional processors operate in standard (90 second), rapid (45 second), or "Kwik" (30 second) mode, and can be varied to operate in an extended-cycle mode, such as described in L. Taber & A. G. Hans, "Processing of Mammographic Films: Technical and Clinical Consideration," Radiology, Vol. 173, No. 1, pages 65-69, October 1989. In the latter mode, processor speed is lowered and chemistry temperature is raised to enhance image contrast for better detection of changes in density of fibrous tissue. The new processors will be settable as to run parameters, including transport speed in order to be able to use the same processor for multiple processing modes.
The operations and functions of such processors are typically handled under control of electronic circuitry including a microcomputer connected to various process sensors and subsidiary controls to receive and dispense electronic signals in accordance with predefined software program instructions. Examples of such control circuitry are shown in U.S. Pat. No. 4,300,828 and in copending, commonly-owned U.S. patent application Ser. No. 07/494,647, entitled "Processor with Temperature Responsive Film Transport Lockout," filed Mar. 16, 1990, the disclosures of which are incorporated herein by reference thereto. The microcomputer may comprise a microprocessor, input/output interface circuitry and one or more memory units, including a read-only memory element (ROM) which contains program instructions and data, such as data in the form of look-up tables. Provision is made in the memory map for a bootstrap memory plane which serves to initiate the system and load the main program at system start-up. Present software updating in processors employing such ROMs is accomplished by physically extracting the memory module from its socket on the control circuit board and inserting a new module including the changed software in its place. Such physical replacement involves equipment downtime and attention by technically trained service personnel. It also entails an unnecessary degree of risk of damage to the memory modules and other processor components due to physical handling.
It is desirable to be able to update product software in the field without having to physically replace components, with less time required by technical service personnel, and with less risk that the modules or processor might be damaged during the updating process. In particular, it is desirable to be able to update processor control circuitry software by downloading software from an external source by means of reprogramming an on-board ROM without removing it from the processor.
Programmable read-only memories (PROMs), such as electrically alterable or erasable PROMs (EAPROMs or EEPROMs), are known which can be erased and reprogrammed by connecting the same within a programmer after removal of the PROM from its primary operating site. The reprogramming of ultraviolet erasable PROMs by means of a minicomputer-controlled programmer is described in F. McIntosh et al., "A Minicomputer-Controlled Read-Only-Memory Programmer," Int. J. Electronics 1979, Vol. 46, No. 2, pp. 193-204. The updating of product software by reprogramming a ROM forming a part of the control circuitry of an automatic film processor without removing the ROM from its normal placement position in the processor is not heretofore known.